There are increasing environmental and governmental requirements for recyclying plastic containers, such as those conventionally used for foodstuffs and beverages. Thus, a consumer must save used containers and return them to a recycling depot.
However, conventional empty plastic containers are bulky to store and handle, consuming a lot of space. They do not stack readily. If a consumer attempts to collapse such containers he encounters great difficulty in that the containers are resilient and tend to re-assume their original shape. Even if they deform, it is with an irregular shape and they still are not readily storable or stackable. As a result there is a need for collapsible and stackable containers, so that are encouraged to recycle.
There is considerable patent art relating to collapsible containers in general. Among them are Shriver in U.S. Pat. No. 4,775,564; Jones et. al U.S. Pat. No. 4,790,361; Akiho U.S. Pat. No. 4,805,788; Hollingsworth U.S. Pat. No. 4,865,211; Dirksing et al. U.S. Pat. No. 4,873,100; and Touzani U.S. Pat. No. 5,002,193. While there are a variety of wall configurations, many of the prior art containers do not collapse to a stable collapsed state; others have complicated geometry.
There is also considerable patent art relating to the stacking of containers. Among these are Stewart U.S. Pat. No. 3,458,355; Hubert et al. U.S. Pat. No. 4,127,207; Schieser et al. U.S. Pat. No. 4,208,955; Niwa et al. U.S. Pat. No. 4,793,516; Brandt et al. U.S. Pat. No. 4,805,793; and Frahm U.S. Pat. No. 5,002,199. While there are many ways for stacking containers in the prior art most art is directed to conventional containers. There appears to have been little effort addressed to the problem of stacking collapsed containers.